advice needed about Zurich places

Dear All, I am arriving at the second part of February to Zurich just for one full day / 2 nights. I do not have any local friends and just don't know where it could be good to go in the evening. I would prefer smth like an informal bar with a life music. Going to the restaurant is also an option but being there along seems for me enough boring :) I would appreciate any recommendations on where a foreigner can go in the city at the evening. Thank you in advance. Karina.